Objective To evaluate the applied values of susceptibility weighted imaging (SWI) in acute ischemic stroke.Methods Totally 40 patients with acute ischemic stroke were included within 72 hours after symptom onset.They adopted multimodal magnetic resonance imaging examination,including regular magnetic resonance imaging sequence (T1WI,T2WI),time of flight MR angiography (TOF-MRA),diffusion weighted imaging (DWI) and susceptibility weighted imaging (SWI).Furthermore,12 of the 40 patients received dynamic susceptibility contrast enhanced perfusion weighted imaging (DSCPWI) examination.Results Of the 40 patients,12 ones had positive results for multiple lesions of cerebral microbleeds (CMBs) by SWI,and the detection rate was 30％.There were 24 patients showed susceptibility vessel sign (SVS) in SWI,and the susceptibility rate was 60％.In the 12 patients received DSC-PWI examination simultaneously,there were 7 cases had the anomaly range by SWI larger than that by DWI while similar to that by DSC-PWI.Conclusion SWI can show SVS and CMBs clearly,estimate ischemic penumbra,know intracranial conditions completely and supply reliable basis for individualized treatment.